My idea about speaker

In my boy hood I live in a town at periphery, not in a city center. Lifestyle was slow there and most of the people were engaged in cultivation for daily livelihood. Life events was Timmy and happenings were less. Very routine life. Most of the time there were no electricity at night. Old people gossip in various tea shop by telling story of his past. Some of the children listen to those story.

One day, I found that music was playing in a tea stall with a loud speaker. Quality of sound was not good but a breakthrough of monotonous life. People understand that good music can make life beautiful. 

The speaker of present improves a lot. During my study of engineering, I found that speaker is a transducer and has good electrical mechanism of producing nice sound. There are various bands of sound which has attenuation and phase shift characteristics.  Research has developed and filtration of various bands of sound has improved. I was wondering with a product of Alexa echo dot, a nice speaker and also smiling to compare of old tea stall's speaker.